look-wood



(No Model.) #Shegts-Sheet 1. R. M. LOOKWOOD & H. BARTLETT.

Transmitter for Telephones.

No. 241,385. Patented May 10,188I...

N. PETERS. Fhoto-Liihugnphe Washington, D. C.

(No Model.) 2 Sheets-Sheet 2.

R. M. LOOKWOOD 8: S. H. BARTLETT;

Transmitter for Telephones.

No.'241,385. Patented Maj 10,1881

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I N. PETERS, Fhnimulhognphan Washington, D. C

UNITED STATES PATENT OFFICE.

ROBERT M. LOCKWOOD AND SAMUEL H. BARTLETT, OF NEW YORK, N. Y.,ASSIGNORS, BY MESNE ASSIGNMENTS, TO MOLECULAR TELEPHONE GOM PANY, orSAME PLACE.

TRANSMITTER FOR TELEPHONE S.

SPECIFICATION forming part of Letters Patent-No. 241,385, dated May 10,1881.

Application filed July'2, 1880. (N model.)

To all whom it may concern Be it known that we, ROBERT M .LOCKWOOD andSAMUEL H. BARTLETT, of the city, county, and State of New York, haveinvented certain new and useful Improvements in Transmitters forTelephones, of which the ibllowing is a full, clear, and exactdescription, reference being had to the accompanying drawings, makingpart of this specification, in which-- Figure 1 represents our improvedtransmitter in section. Fig. 2 represents a side elevation of a vase orstand for supporting the trans mitter, shown applied thereto in dottedlines. Figs. 3 and 4 are plan views of the two carbon buttons or plates.Figs. 5 and 6 represent modifications-in the construction of thetransmitter; and Figs. 7,8, 9, 10, and 11 are detail views illustratingthe same.

A The invention relates to a novel construction of embedded microphone;and it consists in making the microphone of two plates or disks ofcarbon or other conducting material arranged one upon or over the other,one having a central perforation, and the other a cen- 2 5 tral pin orspur passing through said opening, through which connection is made withthe binding-posts or line-wire; in embedding said plates in a block ofcork or other non-resonant material, and in a novel manner of supporting0 said embedded microphone in a stand or support, whereby only the uppersurface of the block in which the microphone is'embedded, and by whichit is covered, is exposed to the direct action of the atmosphericsound-waves,

3 5 all as hereinafter described.

In the accompanying drawings, A B repre sent the buttons or plates ofcarbon or other conducting material, the lower one, A, being made in theform of a fiat ring or of a disk 0 having a central perforation, a, asshown in J chamber, 1), formed in it for their reception,

the buttons fitting snugly within the chamber, and being providedwith acovering, D of cork or other material similar to that of which thenon-resonant block D is composed. Wires 0 e are connected with thebuttons, the one, 0, with the button A directly, and the other, c, withthe pendent spur or pin 1), as shown,and extend thence throughperforations in the cork and supportingstand, either or both, to thebinding-postsff, as shown;

The elements or features above described constitute the transmitter per86, but for convenience in handling, use, 850., we support the block Din a base plate or stand, which may bemade ornamental in design orconfiguration, as shown at G, Fig.2, only the upper face of thenon-resonant block being exposed to the direct action of thesound-waves; This vase or stand is made preferably of lead or othernon-resonant metal; but it may be of wood, '70

rubber, or other material, to give itthe desired weight,and wheretusedin a factory or other building subject to the jar of machinery, shouldbe cushioned on a pad or mat of wool, soft rubber, felt, or othersuitable material, to -7 relieve it, as far as practicable, fromdisturlr ance from the jarring of the building.

In Fig. 6 the block or cork is shown fitted in a socket or cup formed ina metallic baseplate, H, and the pendent spur b on the upper carbonplate or button,instead of being connected by wire with thebinding-post, dips into mercur Y in a cup, I, arranged within asocket inthe base-plate H, and made adjustable up and down in said socket bymeans of a thumbscrew, J, for varying the depth or extent of immersionof the spur or point I) in the mercury. In this case the base-plate H ismade a conductor, and connects the upper button, through the cup ofmercury, with the bindingpost f, and the wire e and binding-post f passthrough or are supported in insulators c 0 of rubber or other suitablematerial, as shown. The base-plate, in turn, is supported in a suitablestand or vase, G, as in the construction shown in Figs. 1 and 2. In Fig.5 the lower button is'not perforated and the position of the upperbutton is re versed, the spur projectiu g upward, as shown. In thisconstruction the central pin or spur, I), has the inner end of adelicate coiled spring, is, (see Fi 8,) connected with it the outer endof said spring being connected by wire with the binding-postf. By thisarrangement of the spring or wire we get the benefit of the elasticityof a long piece of wire within a small space or compass and avoid anybinding or trammeling of the upper button. The form of the button inthis construction is represented in Figs. 10 and 11.

By the construction and arrangement of parts shown we dispense with oneof the pieces of carbon constituting the embedded microphoneshown in ourformer patent, thereby simplil'ying its construction, and we so inclosethe non-resonant material in which the microphone is embedded initssupportin g vase or stand as- What we claim as new is- 1. Inatelephone-transmitter, the two plates or disks of carbon, one of whichhas a central opening and the other a spur passing through saidopening,through which connection is made with the line-circuit.

2. In a telephone-transmitter, the two disks or plates of carbon orequivalent conducting material, one having the central opening and theother the spur, through whiclreonnection is made with the line-wire, incombination with the block of non-resonant materialincasin g andcovering said disks or plates, as described.

3. In a telephone-transmitter, the two disks or plates of carbon ortheir equivalent, constructed as described, and embedded within andcovered by the non-resonant block, in combination with the supportingstand or base ineasing said block and leaving only its upper faceexposed to the direct action of the atmospheric sound-waves,substantially asdescribed.

